


Cholera

by agnosticnun



Category: Shadow Unit
Genre: Gen
Language: English
Status: Completed
Published: 2019-04-01
Updated: 2019-04-01
Packaged: 2019-12-30 15:03:53
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 424
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18317693
Author URL: https://archiveofourown.org/users/agnosticnun/pseuds/agnosticnun
Summary: Arthur Tan discovers Chaz and Hafidha developing a complex computer visualization of unclear purpose.





	Cholera

Arthur Tan stopped and stared, whatever he’d been going to ask forgotten. “What,” he asked, pointing to one of the larger displays, “is THAT?”  
  
Clearly  _that_ , as he put it, was a map. A map showing a good chunk of the eastern seaboard, overlain with dots, swirls and squiggles in different colours. A flowery pattern of loops was drawing itself near Galveston. Had there been gamma activity there? He frowned. Certainly nothing recent.  
  
Chaz glanced at Hafhida, then shrugged. “It’s a spatio-temporal map of the progression of known and suspected gammas... and betas. We’ve been tracing back some of the ones Beale’s turned up. The yellow dots are suspected point of crack, orange first known manifestation.”  
  
“And red for death of gamma?” For some gammas, place and time of death was about the only fact known with much certainty.  
  
“Yes.” Hafhida took over. “See where the lines cross, here and here and here? Brighter colors mean they came closer to overlapping in time.” She flicked her fingers, and map sections popped up on neighboring monitors. Arthur was almost used to the effect.  
  
He studied the map. “You’re looking for transmission patterns?” Because that was the only reason to highlight cracks, or more precisely, the space between crack and manifestation. “Yes." Chaz responded. "Or environmental effects, regional trends, really any regularities.”  
  
Hafs laughed, a sharp unfunny sound. “That’s what he says he’s looking for. Really he’s trying to find the Broad Street Pump.” An apple materialized and she bit into it with unnecessary vehemence.  
  
Athur blinked, but Chaz continued imperturbably “or something like the pump, yes. It can’t be ruled out.” When Tan looked at him quizzically, he explained, “In 1854 a physician named Jon Snow used mapping techniques to analyze a London cholera outbreak. When he compared the map of cholera cases with a map showing public water sources, he realized that a particular pump on Broad Street was the source of the outbreak. It’s one of the first and most famous triumphs of geospatial data analysis.” He paused while Hafhidha silently, perhaps apologetically, called up an illustration of the long ago disease outbreak. He continued, “unfortunately, while we’ve plotted our outbreak, we haven’t found a map of the water supply.”  
  
Returning to the map, Tan followed a pattern of tangles up and across monitors until they disappeared into a bright smear. “Oh. Idlewood,” he recognized. The section enlarged itself as he spoke, dots and lines squirming. Was Hafhidha updating this part of the map in real time?  
  
It looked like a petri dish.

**Author's Note:**

> I originally shared this on Livejournal and posted about it on the SU forums back in 2013. It was prompted by my wondering why Chaz, with his PhD in Statistics, doesn't seem to use any geospatial analysis techniques more complicated than drawing circles on maps.


End file.
